This invention relates to the generation of a video signal from play of a software (e.g., motion picture) carrier, and more particularly to a technique by which two versions of the same motion picture can be stored on a single carrier with a player controlling which version is viewed.
A key to understanding the present invention is to realize that the R-rated and PG-rated versions of the same motion picture will usually be the same for most of the picture. (Ratings may depend upon audio, e.g., expletives, and/or video.) In order to avoid duplicating all of this common material in two different tracks, what is done is to store the common material only once, and to play it during play of both versions. It is in this way that two versions can be stored with no redundancy. (For segments where the only difference between R-rated and PG-rated versions is in the soundtrack, e.g., explicit dialog, the most economical method of providing alternate versions would be by switching only soundtrack material, making use of the xe2x80x9cotherxe2x80x9d audio tracks to be described below.)
In a two-version carrier, each of the video and audio tracks contains three types of information. If the letters A and B are used to represent two different versions of the same material, with the letter C being used to represent that part of the overall recording which is common to the two versions, sections of the track can be identified by the letters A, B and C. If the A version is to be viewed, then all A and C sections must be played; if the B version is to be viewed, then all B and C sections must be played.
In the illustrative embodiment of the invention, data is stored on the disk in blocks. Each block contains not only video data, but also audio data, subtitle data and other data to be described. Each block may represent a number of frames of the motion picture, but in most cases numerous blocks will be read in succession because they will all be of the same type, A, B or C. It is only when the last block in an A group, a B group or a C group is processed that it may be necessary to jump over the next group of blocks. Since the C blocks are processed for both versions, there is no need ever to skip over a group of C blocks. Depending on which version is being viewed, however, all A blocks are skipped, or all B blocks are skipped. (Similar considerations apply to three or more versions on the same carrier.) The basic technique which is used is to include in each block a code which directs the system to the next block either the succeeding block, or one further along the track. Where blocks must be skipped over, the current block includes a pointer, i.e., an address pointing to the next block further along the track which is required in the version being played.
The lead-in section of the disk includes four bits which constitute a xe2x80x9cmultiple versionxe2x80x9d code. The player is informed not only whether there are two versions of the same presentation on the disk, but also what the choices are with respect to them. A player designed to play the disk of the invention includes a parental lock option. If the option key is on, it means that the player will not play R-rated motion pictures. The four bits in the code which is first read by the player identify whether there are two versions or only one, if there are two versions then which of them is R-rated, and whether the parental lock option is to be implemented (if it is keyed on in the player) or a different criterion is to be used in selecting which version is to be played. The usual situation is where the parental lock option is implemented. Depending on the ratings of the two versions on the disk and whether the parental lock has been keyed on, the viewer may be allowed to play one or both versions, or perhaps neither. The appropriate choices are provided on a menu display, from which the user selects a version for play.
If the four-bit version code informs the player that the criterion for version selection is not a rating, but rather something else, the player must determine what that criterion is in order to form the appropriate menu display for the user. In such a case, following the version code in the lead-in section of the disk, software is provided to control the formation of the display which identifies the available versions, and how a version is to be selected for play in accordance with user inputs. This technique of providing software for controlling the selection of a version extends use of the invention beyond parental lock-out of adult-rated motion pictures.
The invention is disclosed in the context of an overall system which offers numerous advantageous features. The entire system is described although the appended claims are directed to specific features. The overall list of features which are of particular interest in the description below include:
Video standard and territorial lock out.
Play in multiple aspect ratios.
Play of multiple versions, e.g., PG-rated and R-rated, of the same-motion picture from the same disk, with selective automatic parental disablement of R-rated play.
Encrypted authorization codes that prevent unauthorized publishers from producing playable disks.
Provision of multiple-language audio tracks and multiple-language subtitle tracks on a single disk, with the user specifying the language of choice.
Provision of multiple xe2x80x9cotherxe2x80x9d audio tracks, e.g., each containing some component of orchestral music, with the user choosing the desired mix.
Variable rate encoding of data blocks, and efficient use of bit capacity with track switching and/or mixing, to allow all of the above capabilities on a single carrier.